Automatic consistent sampling for data analysis

Abstract

A method, computer program product, and system for analyzing data within one or more databases, comprising selecting one or more databases for analysis, each database comprising one or more database objects comprising one or more data values, applying a function to each data value in each database object within the one or more databases, where the function produces function values limited to a predetermined range, identifying for analysis the data values producing a certain function value within the predetermined range to form a sampled data set, and analyzing the sampled data set to determine relationships between the database objects within and across the one or more databases.

What is claimed is: 
     
       1. A computer-implemented method of analyzing data within one or more databases, comprising:
 selecting one or more databases for analysis, each database comprising one or more database objects comprising one or more data values, wherein the data values in each database object are arranged in columns; 
 applying a function to each data value in each database object within the one or more databases, wherein the function produces function values limited to a predetermined range; 
 identifying for analysis the data values producing a certain function value within the predetermined range to form a sampled data set; 
 identifying for analysis the data values that produce function values other than the certain function value and reside in one or more columns lacking high cardinality to form an unsampled data set, wherein a column has a high cardinality when data values in the column satisfy one or more from a group of a predetermined cardinality threshold and a predetermined selectivity threshold; and 
 analyzing the sampled data set with the unsampled data set by matching data values within these data sets to determine relationships between the database objects within and across the one or more databases. 
 
     
     
       2. The method of  claim 1 , wherein said analysis further comprises determining one or more primary key-foreign key relationships between the database objects within and across the one or more databases. 
     
     
       3. The method of  claim 1 , wherein a column is a high cardinality column if a number of data values in the column that produce the certain function value exceeds the predetermined cardinality threshold. 
     
     
       4. The method of  claim 1 , wherein a column is a high cardinality column if a number of unique data values in the column divided by the number of data values in the column exceeds the predetermined selectivity threshold. 
     
     
       5. The method of  claim 1 , wherein the function is a hash function. 
     
     
       6. The method of  claim 1 , wherein the database objects are tables.